Leaking Shower

I am trying to help a friend during his lower level bathroom remodel. The bathroom right above rains when the shower is run.

I ran the tub for a while and no water leaked down. I have the ceiling below open so I can see the entire drain (which is all new abs).

Now the "diverter" for the tub/shower is simply a pull-up control on the tub spout that blocks off the spout. My concern is that it (the tub spout) isn't threaded onto the pipe from the wall but rather just slipped on and then held in the back with a set screw.

I was thinking that maybe water is working it's way back down the pipe when the stop is pulled up?

Any thoughts or advice. I went and picked up a version of the tubspout that threads on, thinking I can solder a male thread to the pipe stub and cap it off. Then if it continues to leak I think it is either in the shower head fitting or at the valve somewhere.

Tub spouts typically come in two varieties, the one you have - a compression fitting, and the other, that screws on. Many of each variety are available and work fine. The compression type does, though, require that the pipe be in good shape and the o-rings can't be damaged when installing. A couple of things can compromise the installation - tightening the set screw too much and deforming the pipe or not cleaning off the burrs at the end of the pipe and slicing the o-rings. If the thing is really old, the o-rings could be getting dry and cracking. It is usually pretty easy to see if that is the source of the leak. Put it in the shower mode and watch! Make sure that the shower is hitting the tub and not the walls. This eliminates the walls, but not the pipe up to the showerhead as a source. If you don't get any leaks then, move the showerhead around so it hits the walls and see what happens.

Basically, unless it is plumbing, it is the wall construction. Note, neither the tile nor the grout is totally waterproof, but they significantly protect against liquid water from getting through. They will allow moisture vapor to get through and condense, but that would not cause a stream of water, only enough to rot the studs over time. There should be a lip on the tub to prevent liquid from getting past, but if the tub is not set level and there is any damage, it can leak through there.

Check any caulking at the tub/wall junction, and if compromised, clean it out, let it dry, then recaulk. You should have caulk there, not grout.

A failure of grout should not cause a leak of the nature you are talking about.

www.johnbridge.com is a great place to get tiling help, if you need it.

The walls/caulk tub suround was the first suspect b/c it is in disrepair, but I quickly eliminated that problem by running the shower (which thankfully has a jet type spray) into the tub and not getting any water on the walls. The problem still happens. So I am left with the bath spout or shower head piping.

If it was the tub spout would water be apparent toward the back of the spout? When the compression type like I have fail, does it create like a finger over the hose effect or will the water make it's way past the o-ring and just flow down along the pipe.

BTW---I found this place from johnbridge

Most likely culprit from what you have talked about is the shower arm. The shower head screws into this angled pipe and the arm screws into a pipe behind the wall. Wrap the shower arm with a rag and try to tighten with a channel lock. If this slows down the leak, you may need to replace the arm or remove it and add teflon tape to the threads begore retightening it.

The way the spout is attached to the pipe doesn't change how the divertor works. Bascially, the water comes out of the tub/shower valve and goes two directions. Because the pipe to the shower is longer, higher, the water goes out the spout because it is easier. Once you block the spout, it now goes out of the shower head. It would likely run along the pipe if it was leaking there, but there are numerous otherplaces it could be leaking. The more likely one is where the shower arm is connected to the riser pipe from the valve - is it loose?